The first experiment in which the plasma in a tokamak was fuelled with tritium was carried out at JET in November 1991 using 0.1g of tritium. The design, construction and safety justification of the tritium handling plant for the final D-T phase at JET using 90g of tritium has been essentially completed. Valuable experience in tritium handling, clean-up and waste disposal has been gained which is directly relevant to the use of tritium in future JET operation and to controlled fusion research in general.